tonkin



(No Model.) 2 Sheets-Sheet I.

J. J. TONKIN.

VALVE MEOH'ANISM.

No. 360,741.. Patented Apr. 5, 1887.

III

i (No Model.) 2 Sheets-Sheet 2.

J. J. TONKIN.

VALVE MECHANISM.

N0. 360,741. PatentedApr. 5, 1887.

WITNESSES INVENTOR I John IJZZUQ'R,

, By izisflttome s It PETERS Mo-Lilhonplwn Wuhingwn, D. Q

UNITED STATES PATENT OFFICE.

JOHN J. TONKIN, OF OSYVEGO, NEWV YORK, ASSIGNOR TO THOMSON KINGS- FORD,OF SAME PLACE.

VALVE M-ECHANISM.

SPECIFICATION forming part of Letters Patent No. 360,741, dated April 5,1887.

Application filed December 27, 1886. Serial No. 222,624.

To aZZ whom it may concern.-

Be it known that I, JOHN J. ToNKIN, of 0swego, in the county of Oswegoand State of New York, have invented certain new and useful Improvementsin Valve Mechanisms, of which the following is a specification,reference being had to the accompanying drawings, in which- Figure 1 isa plan view; Fig. 2, a central section; Fig. 3, a section at rightangles with Fig. 2; Fig. 4, another plan with different detailsindicated in dotted lines.

The object of my improvements is to provide for use, in connection witha main slidevalve of ordinary character, a removable automaticcut-otf-valve mechanism which may be operated by a governor to open theports when the engine has a heavy load and to close them when it has alight load, thereby automatically regulating the cutoff to correspondwith the varying work to be done by the engine. I provide such a cut-offvalve so constructed and arranged that it may be removed at will fromthe steam-chest, leaving the ordinary slide-valve to work alone, wherebyrepairs can be made to the slide-valve without in the meantimediscontinuing the use of the engine.

Referring to the letters upon the drawings, A indicates the steam-chest;B, the main slidevalve; 0, the main-slide-valve stem, the usualsteam-ports, a a, and exhaust-port, I), being provided.

D indicates agovernor-stem, operated by any ordinary governor, E, andprovided with collars F F for the purpose of operating levers G G,pivoted at H H. These levers engage, by a ball -and-socket joint, withthe cut-off valves I I, which slide in ways K and on the upper surfaceof the main slide-valve.

L indicates a frame for supporting the levers and the automaticcutoff-valve stem.

This frame, of which the guideways form a part, as illustrated, can bescrewed to the side wall of the steam-chest, as shown, so that bywithdrawing the screws the frame and automatic cut-off valve and stemcan be removed (No model.)

from the steam-chest at will, leaving the main slide-valve to operatealone.

The operation of the automatic cut-off valve is as follows: Oscillatingmotion is communicated to the pivoted levers by means of the verticalreciprocating movements of the governor-stem, and the levers in turnslide the cut-off valves over the steam-ports, or away from over them,according to the variations of the speed of the-engine which may becaused by the varying load of the engine. For example, suppose the maincut-off valve, which is always set to out off at some definite part ofthe stroke, be set so as to cut off the steam at a three-quarter stroke.When the engine has a heavy load, the automatic valves will open theport so as to let on afull head of steam for three-fourths of thestroke; but when 6 5 there is a lighter load, not requiring steam for somuch of the stroke, the slide-valves will close, so as to out off thesteam at less than a three-quarter stroke, according to the needs of theengine for the work to be done. the advantage of providing for takingout the automatic cut-off and its supporting -frame bodily, theconstruction and arrangement of the parts for operating the automaticcut-off valves is of great simplicity.

Having described my improvement, what I claim to be new, and desiretosecure by Letters Patent of the United States, is

The combination, with the steam-chest and a main slide-valve, of theautomatic cut-off valves, the pivoted levers G G, oscillated by thegovernor-stem D and governor E to operate the cut-off valves, and theremovable cutoff-valve frame L, whereby the cutoff-valve mechanism canbe removed bodily and the 8 work of the engine continued without it,substantially as set forth.

In testimony whereof I have hereunto subscribed my name. 1

JOHN J. TONKIN.

WVitnesses:

MARCUS S. HorKINs, G. P. ELwELL.

Besides 7o

